1. Field of the Invention
The present invention relates to a head-end system for providing a two-way video on demand (VOD) service and a service method thereof and, more particularly, to a head-end system for providing a two-way VOD service in which an audiovisual (AV) which is processed to be replayed in real time based on a Java virtual machine and a Java TV/GEM standard middleware and an application related to the AV which is processed to be replayed in real time can be simultaneously provided without multiplexing of a discrete multiplexer and a service method thereof.
2. Description of the Related Art
A conventional data broadcasting is greatly divided into three: a cable TV data broadcasting, a satellite data broadcasting and a terrestrial digital TV data broadcasting. The cable TV data broadcasting uses an open cable application platform (OCAP), the satellite data broadcasting uses a multimedia home platform (MHP), and the terrestrial digital TV data broadcasting an advanced common application platform (ACAP).
A globally executable multimedia home platform (GEM) is a middleware which is developed focusing on interoperability so that a MHP method derived from a digital video broadcasting (DVB) method can be used in all methods. It uses a MHP standard at maximum and has been developed in consideration of both a technical restriction and a regional matter. It is not used alone but is used in a framework defined in a standard based on MHP.
A design rule of the GEM standard is defined so that applications produced by content producers can be interoperated with receivers based on other GEMs.
The GEM standard describes an application program interface (API), a protocol and a content format so that an MHP application can be driven in all iTVs and has an application to be provided through a network communication service rather than a DVB broadcasting service.
After the GEM was introduced, the federal communications commission (FCC) published a draft ACAP standard for harmonizing a digital TV application & software environment (DASE) which is an American terrestrial data broadcasting standard and the OCAP which is a cable data broadcasting standard in December 2003. Since OCAP 1.0 is in the process of standardization based on MHP 1.02, MHP which is an European data broadcasting standard, DASE which is an American terrestrial data broadcasting standard, and OCAP which is an American cable data broadcasting standard will be developed to ACAP. Most of companies in Korea employ a MHP middleware which is commercially available in consideration of such a development process.
Currently, KT Corp. in Korea and FastWeb in Italy are planning a two-way interactive VOD service which costs millions of dollars.
Transmission of a two-way application needs muxing equipment. However, the muxing equipment costs tens to hundreds of thousand dollars and should be installed in every telephone office, whereby there is a problem in that an initial investment cost is very high.
For these reasons, it has been considered to provide an application by using a http or https protocol which is relatively chip.
However, in conventional Java, an MPEG-2 based service is multiplexed and then transmitted together with an application information table (AIT) which is information of an application defined in MHP and GEM and a digital storage media-command and control (DSMCC) which is a mechanism for transmitting files defined in MPEG-2 based on MPEG-2, or an MPEG-2 TS with only AV is expressed.
Two-way standards such as GEM, MHP, ACAP, and OCAP are groping for a method for providing the AIT and application files through a web server, but there is no method for interoperating such an application and the AV so far. Therefore, a two-way digital broadcasting industry urgently needs a technique for multiplexing VOD information and VOD-related application information to be simultaneously serviced.